Although the first useful lasers were developed in the 1960's, recent advances in laser and fiber optic delivery systems have greatly enhanced the use of this technology in the field of medicine and other fields. Today there is a wide variety of laser delivery systems available on the market intended for use in a wide range of applications.
A common type of laser known as a CO2 laser delivers radiation with a wavelength of 10.64 microns. However, in order to focus or channel the radiated energy produced by a CO2 laser it is necessary to configure sets of mirrors in certain ways. These systems are typically large and expensive. With the advent of the Nd:YAG type laser delivering electromagnetic energy at a wavelength of 1.064 microns, it became possible to generate and focus the laser radiation through a silica core optical fiber. Recently, use of the Holmium:YAG, Erbium:YAG, pulsed dye, diode, excimer, Alexandrite, ruby, Ti:Sapphire, KTP and Argon lasers have become more widespread as new applications are being developed. Thus, fiber optic surgical tools have become important in certain procedures. The range of their utility is still being explored and discovered.
In medical applications, laser energy and optical fibers are used in different ways, including incision, necrosis or killing of live tissue, excision or removal of tissue and structure, removal of surface layers of skin, tattoos, etc., and cauterization of tissue. Cauterization and necrosis of living tissue is accomplished by coagulation, or more precisely with respect to the laser itself, by photocoagulation of contacted or penetrated tissue. In this process the laser beam causes the proteins in the contacted tissue to heat up rapidly and thermally denature. This essentially kills living tissue and seals blood vessels. In practice, during an incision procedure cauterization of the incised tissue is likely to occur simultaneously. Thus, laser surgery is often characterized by an absence of bleeding during the surgery, both in open and endoscopic protocols.
Given the recent advances in related surgical and other laser technology, it has become increasingly important to provide users of such equipment with a range of specific tools, accessories and laser generating systems. Many manufacturers are engaged in these activities. A range of laser drivers or laser generators are now in use in hospitals and clinics throughout the world. These laser systems are expensive and constitute major capital investments. Additionally, there is a very broad range of accessories to be used with these laser systems. Unfortunately, the laser systems available to the surgeon are not always compatible with the fiber optic accessories that the surgeon needs.
On a laser generating system there is always an output interface between the device generating the laser energy and the device transmitting the laser energy. This interface must provide several functions. First, the interface must be convenient to use. Bayonet mounted, screw-in or other quick-connect means are often provided on the laser generators. Similarly, most fiber optic scalpels, probes and other devices incorporate a factory preassembled fiber connector to be used with a specific type of laser generator. In the industry, there are several types of fiber connectors which have become standard and are used widely, due either to market share of certain manufacturers as well as industry standards which have been developed in the last decade or two. One such standard connector is known as the SMA 905 connector. Another is the proprietary design laser delivery device or other laser peripheral device connector called the EZ Connector (trademark of Xintec Corporation). The fiber optic waveguide is connected to a metal tip which aligns and directs the beam into the fiber. This metal tip is affixed to the optical fiber. A bayonet type connector has a spring loaded mounting system (or some sort of keyed, insert and turn to lock) so that the tip can be brought into close contact or adjacent position with the output port of a laser source. Thus, as the spring is elongated and the bayonet mounting is employed, the fiber connector will ensure an efficient and safe transmission of laser energy into the proximal end of the optical fiber. Other types of connectors, such as the EZ Connector and others, generally have some sort of system whereby the proximal end of the fiber is positioned precisely and the fiber connector itself maintains the integrity of the interface between the laser source and the optical fiber instrument. It is important to note that the present invention includes the embodiment wherein a bare fiber is inserted into the multi-use connector adapter.
The interface assembly must provide an accurate and precise connection and transmission of the laser energy. Typically, a laser driver will employ a series of lenses or other focusing apparatuses such that the output of the laser can be directed entirely or as nearly entirely as possible into the receiving end of the optical fiber accessory. Many of the connectors available today as standard equipment on laser drivers as well as associated accessories transmit significantly less than 100% of the energy available at the interface. This is due to poor design and inefficient coupling of the optical fiber assembly to the laser source.
Finally, all laser delivery systems require critical safety interlocks to safeguard against injury during operation. A stray laser beam can cause serious injury to operating room personnel or equipment or to the patient or doctor themselves. For example, an instantaneous flash of laser energy at 1.064 microns delivered at a rate between 20 and 100 watts, typical usage rates, can cause permanent eye damage, blindness or injury to other bodily tissue.
One such safety feature of laser generating systems comprises an interface assembly interlock system. This type of system insures that the laser cannot be operated unless properly connected to a delivery system. The interlock can be mechanical, electro-mechanical or electrical. In one system, an "electronic signature" is used. In this arrangement, at the laser output interface with the delivery apparatus, a distinctive electrical signal is produced by the coupling of the apparatus and the laser generator such that absent said distinctive electrical signature, the laser generator will not operate. This ensures that a proper connection is made between the laser and the delivery system and will prevent the transmission of laser energy unless and until the transmission is intended. Otherwise, stray laser beams can cause serious bodily and property damage.
The principle problem with all of the laser systems described above is that each manufacturer's equipment utilizes a slightly different connector and interface system. However, if a certain medical facility has invested in a laser generating system, the delivery system or other accessory options available to that facility are limited by the range of products manufactured by the same manufacturer of the laser generating system. There is a high degree of incompatibility among product designs and often certain laser equipment is unavailable to a medical practitioner due to the variations in laser connector designs. Although many of the accessories available today have become industry standards and commonplace among users, there is still a wide range of accessories which are manufactured by different manufacturers according to individual manufacturer's specific criteria and specifications.
U.S. Pat. No. 4,722,337 (Losch et al) discloses a medical laser peripheral and connector system having essentially two portions, a connector plug portion and a fiber portion. Both portions are fused together. Thus, after use of the delivery system, the entire assembly must be discarded since the optical fiber portion cannot be reused.
U.S. Pat No. 4,785,805 (Joffe et al) discloses a two piece disposable laser delivery system which is also comprised of two separable portions. One portion, the distal detachable tip, is reusable while the other portion is disposable and can be replaced. However, the reusable portion is designed to be used only with a specific type of disposable portion and is, therefore, not suitable for use with other disposable fiber optic delivery systems.
It is therefore an object of this invention to overcome the limitations of the above cited products, namely inherent design non-compatibility between various types of commercially available laser equipment, including laser generators and delivery systems.